Hi,
When validating the mandatory fields, the focus is always on the first field of the last column.
According to the logic (javascript function OsPage_ClientValidate), the field that should be focused should be the first field with error of the first column (happens in all devices - desktop, tablet and phone).
It happens for all patterns of Webpatterns> Structure
More details:
On browser
var OsPage_ValidatorsOrder = new Array("Theme_wt18_block_WebPatterns_wt13_block_wt6_wtCommandLine", "Theme_wt18_block_wtMainContent_WebPatterns_wt14_block_wtColumn2_wt25", "Theme_wt18_block_wtMainContent_WebPatterns_wt14_block_wtColumn2_wt26", "Theme_wt18_block_wtMainContent_WebPatterns_wt14_block_wtColumn2_wt17", "Theme_wt18_block_wtMainContent_WebPatterns_wt14_block_wtColumn1_wt28", "Theme_wt18_block_wtMainContent_WebPatterns_wt14_block_wtColumn1_wt7", "Theme_wt18_block_wtMainContent_WebPatterns_wt14_block_wtColumn1_wt23");